21115356017 has 12 divisors (see below), whose sum is σ = 24611622336. Its totient is φ = 18062873640.

The previous prime is 21115356007. The next prime is 21115356023. The reversal of 21115356017 is 71065351112.

It is not a de Polignac number, because 21115356017 - 2⁶ = 21115355953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21115356007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 403709 + ... + 453002.

It is an arithmetic number, because the mean of its divisors is an integer number (2050968528).

Almost surely, 2^21115356017 is an apocalyptic number.

It is an amenable number.

21115356017 is a deficient number, since it is larger than the sum of its proper divisors (3496266319).

21115356017 is an equidigital number, since it uses as much as digits as its factorization.

21115356017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857228 (or 857221 counting only the distinct ones).

The product of its (nonzero) digits is 6300, while the sum is 32.

The spelling of 21115356017 in words is "twenty-one billion, one hundred fifteen million, three hundred fifty-six thousand, seventeen".